<?php
        include 'conn.php';
        $conn=mysql_connect($host,$user, $passwd) or die("Database connect fail".mysql_error());
    mysql_select_db("$database",$conn) or die("Database Access Failure ".mysql_error());
        $isbn=$_POST['isbn'];
        $sql="select `b_id` from `books` where `isbn`='$isbn'";
    $result=mysql_query($sql);
    $num=mysql_num_rows($result);
    if($num>0)
    {
        echo "<font color=\"red\">This ISBN has exist!</font>";
    }
    else
    {
        echo "<font color=\"green\">This ISBN Is Ok!</font>";
    }

?>